红人店铺lauout计算高度缓存，review by Redding

@@ -50,6 +50,7 @@ export default class RedBrand extends Component {
         this._calculateSectionRealHeight = this._calculateSectionRealHeight.bind(this);
         this.containerHeight = 0;
         this.sectionData = [];
+        this.layoutLenghtOffesetForIndex = {};
     }
 
     _onPressLaunchProfile(value){
@@ -66,10 +67,6 @@ export default class RedBrand extends Component {
         } else {
             this.refs.redBrandList && this.refs.redBrandList.scrollToLocation({itemIndex: 0,sectionIndex: 2, viewPosition: 0, animated: false});
         }
-
-
-
-
         this.props.onPressProductFilter && this.props.onPressProductFilter(value);
     }
 
@@ -85,6 +82,7 @@ export default class RedBrand extends Component {
             launchProfile,
             productListForNew,
             shopsdecorator,
+            fliter,
         } = this.props;
         let result ={
             length: 0,
@@ -92,11 +90,13 @@ export default class RedBrand extends Component {
         }
         let realContainerHeight = 0;
         let countNumb = 0;
-        dataSource.map((item, index) => {
+        for (var i = 0; i < dataSource.length; i++) {
+            let item = dataSource[i];
             if (item.key == 'ShopBanner') {
                 if (!shopsdecorator || shopsdecorator.template_type != '1') {
                     result.length = Math.ceil((234/750)*width); //header
                     if (countNumb == layoutIndex) {
+                        this.layoutLenghtOffesetForIndex['fliter' + fliter + 'row' + countNumb] = result;
                         return result;
                     }
                     realContainerHeight += Math.ceil((234/750)*width); //header
@@ -104,13 +104,20 @@ export default class RedBrand extends Component {
             }else if(item.key == 'brandReource') {
                 realContainerHeight += 44; //height of RedBrandStoreFilter
                 countNumb++;
+                if (countNumb == layoutIndex) {
+                    result.offset = realContainerHeight - 44;
+                    result.length = 44;
+                    this.layoutLenghtOffesetForIndex['fliter' + fliter + 'row' + countNumb] = result;
+                    return result;
+                }
                 let sectionDataSource = item.data;
                 if (sectionDataSource.length == 0) {
                     result.offset = realContainerHeight;
                     result.length = 0;
                     return result;
                 }
-                sectionDataSource.map((shopsdecoratorItem, index) => {
+                for (var i = 0; i < sectionDataSource.length; i++) {
+                    let shopsdecoratorItem = sectionDataSource[i];
                     let validFloorData = false;
                     result.offset = realContainerHeight;
                     if (shopsdecoratorItem.get('module_type') == 'coupon') {
@@ -242,17 +249,21 @@ export default class RedBrand extends Component {
                         countNumb++;
                     }
                     if (validFloorData && countNumb == layoutIndex) {
+                        this.layoutLenghtOffesetForIndex['fliter' + fliter + 'row' + countNumb] = result;
                         return result;
                     }
-                });
+                }
+
             }else if (item.key == 'productList') {
                 let brandFilterContainerHeight = this.props.fliter == '2' ? 84 : 40;
                 countNumb++; // filter
                 if (countNumb == layoutIndex) {
-                    return {
+                    result = {
                         length: brandFilterContainerHeight,
                         offset: realContainerHeight
-                    }
+                    };
+                    this.layoutLenghtOffesetForIndex['fliter' + fliter + 'row' + countNumb] = result;
+                    return result;
                 }else if (layoutIndex > countNumb) {
                     let rowHeight = Math.ceil(254 * width / 320);
                     let rowMarginTop = Math.ceil(10 * DEVICE_WIDTH_RATIO);
@@ -260,10 +271,11 @@ export default class RedBrand extends Component {
                     realContainerHeight += brandFilterContainerHeight;
                     result.length = rowHeight + rowMarginTop + rowMarginBottom;
                     result.offset =  realContainerHeight + (layoutIndex - countNumb) * result.length;
+                    this.layoutLenghtOffesetForIndex['fliter' + fliter + 'row' + layoutIndex] = result;
                     return result;
                 }
             }
-        });
+        }
         return {
             length: 0,
             offset: realContainerHeight,
@@ -272,8 +284,18 @@ export default class RedBrand extends Component {
 
 
     getItemLayout(data, index){
-        let sectionInfo = this._calculateSectionRealHeight(this.sectionData, index);
-        return {length: sectionInfo.length, offset: sectionInfo.offset, index}
+        let {fliter} = this.props;
+        let key = key = 'fliter' + fliter + 'row' + index;
+        let sectionInfo = {
+            length: 0,
+            offset: 0,
+        };
+        if (this.layoutLenghtOffesetForIndex[key]) {
+            sectionInfo = this.layoutLenghtOffesetForIndex[key];
+        } else {
+            sectionInfo = this._calculateSectionRealHeight(this.sectionData, index);
+        }
+        return {length: sectionInfo.length, offset: sectionInfo.offset, index};
     }
 
     renderSectionHeader(section) {